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arXiv 2402.06597quant-phcond-mat.stat-mech
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自由费米子受监控系统中不同 unraveling 的影响

The impact of different unravelings in a monitored system of free fermions

Giulia Piccitto, Davide Rossini, Angelo Russomanno

AI总结:

针对退相自由费米子链的两种随机测量unraveling,研究发现测量算符分布存在单峰-双峰分岔且临界测量强度相近,同时逆参与比呈幂律标度体现多重分形行为。

摘要:

我们研究了一条发生退相的自由费米子链,该系统可通过两种不同的随机测量协议(即 unraveling)来描述:量子态扩散协议与量子跳跃协议。两种协议均能使系统态保持斯莱特行列式形式,因此可处理规模相当大的系统。我们发现,沿量子轨迹的测量算符分布存在分岔现象——即该分布的形态会从单峰变为双峰的临界点。两种 unraveling 下出现该现象的测量强度值相近,但分布特性与转变特征存在差异,反映了两种测量协议的对称性不同。我们还研究了斯莱特行列式分量的逆参与比随系统规模的标度关系,发现两种 unraveling 下、任意非零测量强度下均存在幂律标度,标志着多重分形行为。

英文摘要:

We consider a free-fermion chain undergoing dephasing, described by two different random-measurement protocols (unravelings): a quantum-state-diffusion and a quantum-jump one. Both protocols keep the state in a Slater-determinant form, allowing to address quite large system sizes. We find a bifurcation in the distribution of the measurement operators along the quantum trajectories, that's to say, there is a point where the shape of this distribution changes from unimodal to bimodal. The value of the measurement strength where this phenomenon occurs is similar for the two unravelings, but the distributions and the transition have different properties reflecting the symmetries of the two measurement protocols. We also consider the scaling with the system size of the inverse participation ratio of the Slater-determinant components and find a power-law scaling that marks a multifractal behaviour, in both unravelings and for any nonvanishing measurement strength.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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